The present invention relates to an ultrasonic wave diagnosis apparatus for enabling calculi present in a living body to be crushed by an ultrasonic wave and tumors, such as the cancers, to be cauterized.
In recent years, the trend now receiving attention in a medical field of treatment has been toward the treatment called an MIT (Minimally Invasive Treatment).
As one example, a calculus crushing apparatus has been practically realized whereby the calculus is invasively treated/crushed by irradiating a powerful ultrasonic wave from an external source at a calculus site in the living body. This has greatly changed the aspect of medical treatment on the calculi at the urinary organs. As such a powerful ultrasonic wave generating source there are known an underwater discharge, an electromagnetic induction, a micro-bursting, a piezoelectric, etc., system. Of these, the piezoelectric system in particular, though being smaller in its ultrasonic pressure in terms of its power, has various advantages of being finer in focal point, free from any consuming component parts, being capable of freely controlling a powerful ultrasonic pressure as well as a focal point position by the phase control of a drive voltage on a plurality of piezoelements, and so on.
In the field of the cancer treatments, on the other hand, the MIT constitutes one of key words. For the cancers in particular, most of their medical treatments have currently been made by a surgical procedure and, in this case, their involved organs, etc. are greatly damaged, many times, in functions and external appearances and the patient, even if surviving such surgical operation, has to suffer a greater burden. For this reason, therefore, there is a strong desire that less invasive procedure be carried out while not affecting the QOL (quality of life).
In such a trend, recent focus has been on the hyperthermic treatment on the malignant neoplasm, that is, the cancer therapy. This is the therapy by which, through the utilization of the difference in heat sensitivity between the cancerous tissue and the normal tissue, only the cancerous cells are selectively killed by applying heat there and maintaining that area to about 42.5 to 43.degree. C. A preceding method of heating is by using an electromagnetic wave, such as a microwave, but it is difficult for this method to selectively heat any deeply-seated tumors because it is due to the electrical property of the living body. And no better therapeutic outcome can be expected for those tumors present at a depth of over 5 cm. For this reason, it may be considered that, for the treatment on the deeply-seated tumors, use is made of an ultrasonic energy capable of reaching their sites with a better focus.
With such a hyperthermic treatment one step further it has also been considered that the tumor tissue is momentarily thermodegenerated and necrotized by heating, to over 80.degree. C., a tumor site by a sharply focused, powerful ultrasonic wave generated from the piezoelements.
In this medical treatment, unlike the conventional hyperthermia, a very powerful (several hundreds to several thousands W/cm.sup.2) ultrasonic wave is applied to a region restricted at and near its focal point and, therefore, only that region is instantly thermodegenerated/necrotized. And since it is necessary to cauterize the whole affected region while accurately positioning that focal point, a focal point positioning technique becomes of importance.
As one solution relating to this matter, a technique is disclosed by which a heat increasing area during an operation is measured by a temperature distribution imaging utilizing a chemical shift at an MRI.
Further, with regard to the system using an ultrasonic wave alone, a technique is disclosed by which an echo wave is detected from the focal spot area of a therapeutic ultrasonic wave and displayed on the ultrasonic image.
In the ultrasonic wave diagnosis apparatus of a type using a simple B-mode cross-sectional image, in particular, as an "in-operation" monitor, it is not possible to grasp the whole tumor region, at a time, by one image plane of the B-mode cross-sectional image. Even if, therefore, a given cauterizing area is set, there are sometimes the cases where it is shifted relative to an actual affected region in terms of its setting position and range. If, therefore, irradiation is made in spite of this, some area of the tumor is not shot with the ultrasonic wave and, moreover, there is a risk that its surrounding normal tissue will be wastefully injured.
In the conventional ultrasonic diagnostic apparatus, there is no practical means for previously checking, for example, "to what extent an incident path of the therapeutic ultrasonic wave overlaps with the surrounding organs" or "how safe it is to continue its irradiation", in a simple and real-time fashion and there is no way but to follow a pre-operative therapy plan. Under these situations, it has not been possible to make any corresponding correction against the actual movement of the organs and deviation in the incident path of the therapeutic ultrasonic wave. For this reason there is a risk that any important organ will unintentionally be adversely affected upon irradiation with the ultrasonic wave on its way and that, during the shifting of the ultrasonic wave, its applicator will be aimed at an area away from its originally intended site.
In the case where the diagnostic apparatus, such as MRI (magnetic resonance imaging) apparatus, is used, during the "in-operation" time, for an image monitoring purpose, it is possible to acquire three-dimensional image data and hence to make such control that any important organ is not unintentionally involved on a way of the therapeutic ultrasonic wave. However, this is simply based on an assumption and it is not possible to simply check "an adverse effect introduced on an intermediate way of any powerful ultrasonic wave from an actual shooting position", "a variation in a positional relation of the respiratory motion, etc., to the surrounding organs and its adverse effect", "any hindrance of the applicator by other sites when it has been moved to an actual shooting position", and so on.